Denny said: you forgot to add something like France#Density:2012_pop_estimate_Bilan_2010 property Density .
No I did not forget anything, given the Density 'namespace' in the subobject name. IOW your triple merely restates what is discernible from the subobject name. Maybe you should tell me what a "property" property is supposed to represent
At most I made a misstatement that "Estimated is an adjective treated as a subclass of owl:Class" It should say "as an instance of owl:Class"